The present invention relates to a process and to an apparatus for the adhesive connection of the sheets of a multi-sheet, folded printed product, such as a periodical, newspaper, brochure or the like.
A process and an apparatus of this type is described in U.S. patent application Ser. No. 08/258,096, now abandoned corresponding to Swiss CH patent application No. 01 754/93-7 and to EP patent application No. 94 107 767.9. In this disclosed arrangement, the printed product is arranged astride a saddle-like support. A carrying bar with penetration tools in the form of drive-in or boring needles is located above the support. In producing the adhesive connection, a pressing device is first lowered onto the printed product in order to hold the latter, in a defined manner, in abutment against the support. By lowering the penetration tools, through-passages are produced through the fold of the printed product. Upon forming the through-passages or upon withdrawal of the penetration tools, adhesive applied onto the outer side of the penetration tools is transferred onto the sheets over the entire length of the through-passages in order to produce punctiform adhesive bonding. These documents also disclose that the penetration tools could also be arranged on the support instead of being arranged on the carrying bar. The result would be that the drive-in movement would take place from bottom to top i.e. from the inner side of the printed product to the outer side thereof. In this arrangement, however, there is the danger that, upon withdrawal of the penetration tool which has adhesive on its surface, adhesive is rubbed off on the outer side of the outermost sheet and that adhesive is drawn in onto the inner side of the innermost sheet. If the printed product is not fully folded immediately after the introduction of the adhesive, the printed product may no longer be able to be fully folded or no longer be able to be opened fully due to the halves of the innermost sheet sticking together adjacent to the fold. Furthermore, the support may be soiled by adhesive if the printed product is moved along the support after the adhesive is introduced. Adhesive rubbed off on the outer side of the printed product may soil other printed products or parts of the apparatus. Further processing may also be impaired. For example, during stacking of printed products, adhesive which has not yet dried may result in the printed products sticking together.
An object of the present invention is thus to provide a process and an apparatus for the adhesive connection of the sheets of a multi-sheet folded printed product, wherein the adhesive is transferred onto the sheets exclusively in a through-passage.